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Prepare host OS

To start using Live Transcoder, there are few more steps to do, such as login to the Comprimato DockerHub and downloading the docker-compose file. Once you are finished with those, you can start Live Transcoder and save the image of your VM instance for future use.

SSH to the host OS

The easiest way to SSH to the host OS is to use a designated SSH web console by Google Cloud.

You can find it by navigating from the Google Cloud dashboard to Compute Engine and then to VM instances.

Use docker command without sudo

Allow running all docker commands as a non-root user by:

sudo groupadd docker
sudo usermod -aG docker $USER
newgrp docker

Enable coredumps

Enabling coredumps on your host instance helps us perform full diagnostics when an issue occurs.

Using NDI Discovery server

If you plan to utilize NDI Discovery server, you must disable or remove mDNS feature from your host instance first.

High bitrate streaming

To be able to stream high bitrate codecs flawlessly, you need to adjust UDP kernel buffer size of your host instance first.


All Done!

Your instance is fully prepared to run Live Transcoder in docker.


Save the VM image for future

If you plan to spawn more instances or you'd like to avoid setting instances up again for any other reason, you can save the VM instance's image with Live Transcoder as a part of it.

If you'd like to save the environment with Live Transcoder, first, continue to Run Live Transcoder in docker section and then return here and proceed with the guide below.

Save the machine image

From the Google Cloud dashboard, navigate to Compute Engine and then to VM instances.

Select the three-dots menu on the left side of the VM instance and click on Create new machine image.

On the configuration page:

  • Specify Name of your machine image
  • Select whether the image should be bound to a particular Location

And finally, hit the Create button.

Creating an instance using a machine image

From the Google Cloud dashboard, navigate to Compute Engine and then to VM instances.

Click on Create instance button located at the top of the page.

Select the New VM instance from machine image option from the left panel.

Select the desired image and click on Continue.

On the configuration page, you should:

  • Specify a Name for your new instance
  • Check the selected Region
  • And make sure the instance type is switched to GPUs in Machine configuration section

All other parameters match those you used in the past when creating the VM the image is based on.

Proceed by hitting the Create button.

Increase max UDP kernel buffer size

To receive and send streams with high-bitrate codecs (e.g., JPEG2000 or JPEG-XS), Live Transcoder needs to increase the UDP kernel buffer size. However, the default maximum size is too low so it needs to be increased.

sudo sh -c "echo '#kernel send a receive windows buffer sizes' > $SYSCTL_CONF"
sudo sh -c "echo 'net.core.rmem_max=262144000' >> $SYSCTL_CONF"
sudo sh -c "echo 'net.core.wmem_max=262144000' >> $SYSCTL_CONF"
sudo sh -c "echo 'net.core.rmem_default=262144000' >> $SYSCTL_CONF"
sudo sh -c "echo 'net.core.wmem_default=262144000' >> $SYSCTL_CONF"
sudo sh -c "echo '' >> $SYSCTL_CONF"

Now load the updated config file.

sudo sysctl -p $SYSCTL_CONF

Increase txqueuelen for network interfaces

To stream out high-bitrate codecs (e.g., JPEG2000 or JPEG-XS), alsotxqueuelen parameter should be increased for the respective network interface(s). Below, we set the parameter for all available Ethernet network interfaces (by using KERNEL=="e*"):

sudo bash -c 'cat > /etc/udev/rules.d/80-txqueuelen.rules' << EOF
SUBSYSTEM=="net", ACTION=="add|change", KERNEL=="e*", ATTR{tx_queue_len}="10000"

To apply the changes immediately, run:

sudo udevadm control --reload-rules && sudo udevadm trigger

What’s Next

With the instance up and running, you are good to proceed to the next step - Running a docker container with Live Transcoder in it.